My height is 5'4" and my BW is 125 lbs.
This is my theory - you need to be able to do a RLL 10 second static hold with 50% - 75% BW for perfect planche push ups and and 90% - 100% to execute Erbs. (Is that even possible for an elite gymnast???)
This past year, I only trained the isometric planche progressions and presses. I didn't practice much core exercises save for HLL once or twice a month. I didn't do hollow body holds/rocks or arch body holds/rocks. I didn't do any of the dynamic bent arm strength planche progressions that often (which I totally regret.) And I never did any of the back exercises listed in the BtGB book.
I decided to go to my local gym to try out my max RLL. I started at 10 lbs and kept adding 5 lbs. I was able to do 35 lbs for 5 - 6 seconds, but was unable to do 40 lbs. This was the very first time I ever attempted this exercise.
So to hold a full planche for 2 - 3 seconds, I need to be able to hold a static RLL for ~30%+ of my BW for 5 - 6 seconds.
Too bad i don't have something high enough like a pommel horse to elevate my feet :/
The longer you can hold a RLL with heavier weight, the more repetitions you can bust out for Erbs and planche push ups.
What do you guys think?
http://www.youtube.com/watch?v=a8Fiuib57Rw
EDIT: I think I'm going to get a gym membership soon, so I have access to a bench press machine for reverse grip, waistline bench press. I am considering buying a 100 lbs weighted vest for pseudo planche push ups or the other bent arm planche progressions as an alternative to a gym membership.